In this study, full-length cDNA sequences of elovl4a and elovl4b from loath Misgurnus anguillicaudatus were cloned. The full-length cDNAs of loath elovl4a and elovl4b were 2423 and 2054bp, encoding 315 and 300 amino acids, respectively. The deduced amino acid sequences of elovl4a and elovl4b in loath both shared the highest identity with those of Danio rerio, whereas lower identity score between loath elovl4a and elovl4b was present. Temporal expression and tissue expression of loath elovl4a and elovl4b were studied by reverse transcriptase PCR. Results of the tissue expression analyses suggested different functions of loath elovl4a and elovl4b. Functional characterizations of loath elovl4a and elovl4b on synthesis of fatty acids, especially elongating C18 polyunsaturated fatty acids (PUFAs) to longer-chain fatty acids, were studied by heterologous expression in Saccharomyces cerevisiae. Loach elovl4a and elvol4b enzymes were able to elongate all fatty acids tested including 18:2n-6, 18:3n-3, 18:3n-6, 20:4n-6 and 20:5n-3. At last, expression levels of the two elovl4 genes of loath fin cells incubated with 18:2n-6 and 18:3n-3 of different concentrations were measured. Expressions of elovl4a and elovl4b of loath fin cells were significantly up-regulated by 18:2n-6 and 18:3n-3. The results obtained here indicated that loath elovl4 could effectively elongate C18 PUFAs. This was a systematic report of elov14's elongating functions towards C18 and provided an alternative pathway for C20 biosynthesis in fish species. (C) 2017 Elsevier Inc. All rights reserved.